Effect of Vitamin D on Biochemical Parameters of Diabetic Wistar Rats.

&lt;b&gt;Background and Objective:&lt;/b&gt; Diabetes mellitus, characterized by chronic hyperglycemia, disrupts multiple physiological systems. Streptozotocin (STZ)-induced diabetic models replicate these disturbances, including elevated glucose, liver and kidney dysfunction, and altered lipid profiles. Vitamin D, known for its role in bone metabolism, also modulates biochemical and inflammatory pathways, potentially offering protective effects against diabetes-induced metabolic changes. This study aimed to evaluate the effects of vitamin D supplementation on biochemical parameters in STZ-induced diabetic Wistar rats. &lt;b&gt;Materials and Methods:&lt;/b&gt; Male Wistar rats were divided into four groups: control (non-diabetic), non-diabetic+vitamin D, diabetic, and diabetic+vitamin D. Diabetes was induced by intraperitoneal administration of STZ (35 mg/kg). After the confirmation of hyperglycemia (≥250 mg/dL), the supplemented groups received vitamin D (cholecalciferol, 80 IU/day) for 30 days. Glucose, urea, creatinine, amylase, total cholesterol, HDL-cholesterol, triglycerides, AST, ALT, and total bilirubin and fractions were evaluated. Differences were considered statistically significant when p < 0.05. &lt;b&gt;Results:&lt;/b&gt; The diabetic group exhibited a significant increase (p < 0.05) in glucose, urea, creatinine, triglycerides, AST, ALT, and total bilirubin and fractions, as well as a reduction in HDL-cholesterol, when compared to the control group. Vitamin D supplementation promoted a reduction in glucose, urea, creatinine, triglyceride, and AST levels and an increase in HDL-cholesterol in the diabetic+vitamin D group. &lt;b&gt;Conclusion:&lt;/b&gt; Vitamin D showed potential as a modulator of biochemical parameters altered by STZ, indicating a hepatorenal protective effect and improvement of lipid and glycemic profiles.